So the loss of VBU swings very rapidly from the VBU8 CP to the Large unit at the third loss which also reduces the start point of crit number and thus losses from 6 to 5.

The effect of this critical number start point (and it doesn't take more than a few melees to realise critical number is the crux of Impetus) is massive.

When both sides are at VBU 6 or above the critical number for the probable single hit taken remains at 6, a 1 in 6 chance to suffer a permanent loss.

As soon as the 3rd loss is taken the single probable hit means the Large unit is still rolling a 6 to fail whereas the CP are now taking a loss on a 5,6.

In statistical terms (a dry mathematical exercise but one that is at the heart of the game) that means the CP have a 100% greater chance of suffering a permanent loss.

And from there it deteriorates rapidly, the double whammy of losing VBU attack dice and thus generally scoring less hits combined with the ever increasing probability of taking more and more losses when rolling against lower critical numbers means that the CP are likely to be destroyed well before the Large Unit even loses its back rank. Certainly barring some very unlikely results the CP will lose their combat effectiveness well before the large unit does.

So, the proposition I am advancing is this:

For large units losses must be apportioned so that the VBU or the front and rear ranks is as close to each other as possible.

Equally it would mean for the more unusual large units that have a strong melee front unit and slightly weaker missile rear unit (say a 5/3 combination) the melee troops would take the first two losses until the large unit becomes a 3/3 after which the rear unit starts taking losses in turn. This reflects the difficulty that missile troops have in filling the melee ranks in the large unit.